And I'm Steve Inskeep. Juan Zarate is with us next. He was deputy national security adviser during the Bush administration, and he's been thinking of how yesterday's explosions at the Boston Marathon may look from the White House.

Mr. Zarate, welcome to the program.

JUAN ZARATE: Thank you, Steve. I appreciate it.

INSKEEP: So what is the responsibility of the White House, here?

ZARATE: Well, at this point, the White House will be collating as much information as they can, to understand what happened. They'll be - no doubt - looking at what happened overnight, in terms of the forensics; understanding what the FBI and other investigators have been culling from surveillance photos, witness information. As well, they'll be looking at past intelligence that may, in retrospect, put some pieces to the puzzle together as to what may have happened yesterday.

But the White House will no doubt want to understand what happened. And most importantly, I think, for counterterrorism officials, is ensure that there are no follow-on attacks to come, that there are no either copycat attacks or no one related to the attacks that may want to do others harm, either in Boston or anywhere else.

INSKEEP: Well, let's review some information we have from our counterterrorism correspondent, Dina Temple-Raston. Officials, of course, are saying by definition, it's a terrorist attack. They're calling it an improvised explosive device, a not-too-sophisticated bomb. They're also saying, at least initially, there's no obvious signature of some kind of training from overseas. I'm wondering, Mr. Zarate, how does the president's response vary, depending on whether they determined that this is an overseas attack or a domestic attack?

ZARATE: Well, I think the president wants to be very careful, and the White House wants to be careful, that the president not become the first fact witness; that he not be out there declaring facts that may not be there. And certainly with this kind of an attack, where there wasn't suggestive intelligence, apparently, as to what was to come; and certainly not a suggestive type of methodology - this type of bomb could have been just about anyone, someone from a lone wolf like Eric Rudolph in 1996, in the Atlanta attacks; to a downsized al-Qaida attack - and so the president will want to be very careful in couching the context and the language of how he and other White House officials talk about what happened, until there's more information.

INSKEEP: So granting that what we don't know is larger than what we do know here, what does the choice of targets tell you?

ZARATE: Well, certainly, it was a soft target, in the sense that this was not a government building. This wasn't something like the White House or the Pentagon, which are typically targeted by al-Qaida or other terrorist organizations. This was a soft target - meant to harm innocent civilians; meant, also, to attract maximum attention. Whoever perpetrated this understood there would be cameras there, understood there'd be a lot of civilian casualties; also understood there'd probably be a lot of folks who have iPhones and media devices, to capture the results. And so this was intent to terrorize and certainly, to capture some attention. And unfortunately, they achieved that yesterday.

INSKEEP: What do you think about the date? It's tax day. It was Patriots' Day in New England, commemorating battles early in the Revolutionary War.

ZARATE: I think the date itself, as well as the fact that April 19th is the anniversary of the Oklahoma City bombing, you know, has led officials to think that this could be related to an anti-government movement, militia movement. Keep in mind, Steve, that we've had a number of plots, and groups that have been trying to attack government officials and other sites, over the years. And so you have to look at the full range of suspects - everyone from an al-Qaida-inspired individual or group to militia movement, to a lone wolf individual who just wanted to kill a number of civilians in Boston.

INSKEEP: OK, emphasizing again, we don't have answers; we have questions. In about 15 seconds, what is one question that would be on your mind, if you were working at the White House this morning?

ZARATE: I think the main question is: Is this connected to anything else? Will this lead to something else? Will this indicate either that there are networks involved, or that this is a new methodology being applied - either by an al-Qaida group or a militia movement? Regardless, it's of concern.

INSKEEP: OK. Mr. Zarate, thanks very much.

ZARATE: Thank you, Steve.

INSKEEP: Juan Zarate is former lead deputy national security adviser for counterterrorism. Transcript provided by NPR, Copyright NPR.